Manufacture of substantive dyestuffs of the stilbene series



Patented Apr. 9, 1929.

UNITED STATES PATENT} OFFICE.

ALFRED RHEITVER, F BASEL, SWITZERLAND, ASSIGNOR TO CHEMICAL WORKS, FOR- MERLY SANDOZ, 0F \BASEL, SWITZERLAND, A FIR-M.

' MANUFACTURE OF SUBSTANTIVE DYESTUFFS OF THE STILBENE SERIES.

No Drawing. Application filed December 13, 1926, Serial No. 154,658, and in Germany December 19, 1925.

It is known that dinitrostilbenedisulphonic acid, dinitrodibenzyldisulphonic acid or the dyestufi's obtained by the action of caustic soda on p-nitrotoluenesulphonic acid (curcumine S, sun yellow, naphtamine yellow) give valuable substantive colors if the are condensed with, amidoazo-compoun These dyestuffs possess besides good fastness prop erties, as for instance good fas'tness to chlorine, but "an insufiicient fastness to alkali (United States Letters Patent No. 903,284). It is further known that dyestuffs of the stilbene series which are easily oxidizable and are, therefore, not fast to chlorine, can be transformed into dyestuffs fast to alkali and to chlorine by a treatment with oxidizin agent7s (German specifications No. 42,466 and 96,10 It vias, therefore, surprising to find that also the dyestuffs of the United States Letters Patent No. 903,284, which resist to oxidizing agents and are fast to chlorine, can be transformed without any appreciable loss, by a powerful oxidation, into dyestufls which are fast to alkali. Besides the improvement of the fastness to alkaliljthis oxidation efiects a considerable enhancement of the shade, which constitutes a second technical progress of the new process.

SOINa OaNa The following examples illustrate the process, Without limiting it to the proportions and working conditions specified.

Example 1.

50 kg. of the condensation product of dinitrostilbenedisulphonic acid with metanilicacid-azo-m-amido-p-cresolicmethylether, obtained according to Example 3 of the United States Letters Patent No. 903,284, are dissolved in 500 litres of water and 10 kg. of caustic soda of 30 per cent. Then, 200 litres of a sodium hypochlorite solution of 10 per cent are added and the mixture heated to boiling with constant stirring, until the oxidation is achieved. The solution is afterwards new tralized by means of hydrochloric acid and the dyestufi' salted out. It constitutes a red powder which is easily soluble in water with orange red coloration, dissolves in concentrated sulphuric acid with blue color and dyes cotton of bright reddish orange tints. It distinguishes itself easily from the untreated starting material by its good fastness to alkali and by a clearer shade.

The constitution of the condensation prodnot used in this example cannot be exactly defined. It may be represented by the following formula:

SOsNa S'OsNa GH=CH so that the operation of oxidation with 50, may convey to an oxidation product of the following formula:

SOQNS OCH:

N=N N=N OaNa CH:

on=on- No.

SOzNa OsNa Example 2.

50 kg. of the condensation product of dinitrostilbenedisulphonic acid'with sulphanilic 5 acid-azo-a-naphtyl-amine, obtained accordboiling temperature with chlorine introduced the United States Letters Patent No. 951,047

successively and cautiously until the alkali is NaOzS Na0;S

consumed. The resulting dyestufl, which is fast toalkali and of a clearer shade, is then salted out. It constitutes a red powder which is easily soluble in water with red coloration, is dissolves in concentrated sulphuric acid with violet blue color and dyes cotton of orange red tints.

The constitution of the condensation product used in this example cannot be exactly de- 2 fined.v It may be represented by the following formula:

SOaNa SOaNa SOzNa SOaNa so that the operation of oxidation with 0 may convey to an oxidation product of the following formula;

E wample 3.

kg. of the product obtained according to by condensation of curcumine b having the formula:

SOaNa i dGcrgonO-rrk S OsNa heated under reflux until the oxidationis achleved. The solution is then diluted with water, subjected to precipitation with soda,

' filtered hot and the dyestufi' salted out. The

obtained dyestufi' constitutes'an orange powder, which is easily solublein water with yellowish orange coloration; its solution in sulphuric acidis of violet red color. It dyes cotton of yellowish orange tints and is cont'rarily to the starting material fast to alkali and gives a more yellowish and purer shade. It appears impossible to give the exact formula of constitution of the condensation product used in this example, so that the operation of oxidation cannot be exactly represented by a SOzNa SOaNa formula.

What I claim is:

1. A process for the manufacture of substantive dyestufi's of the stilbene series, fast to alkali, consisting in treating with oxidiz- 00 ing agents the dyestuffs, obtained by the condensation of dinitrostilbeneor dinitrodibenzyldisulphonic acid with amidoazocompounds.

2. A process for the manufacture of sub- 05 stantive dyestuffs of the stilbene series, fast to alkali, consisting in treating with oxidizing agents the roducts of condensation of the wdyestuffs obtained by the action of caustic soda on p-nitrotoluenesulphonic acid (curcumine S, sun yellow, naphtamine yellow) with amidoazocompounds.

3. As new products of manufacture, the substantive dyestuffs such as obtained by the oxidation of the products of condensation of dinitrostilbeneor dinitrodibenzyldisulphonic acid with amidoazocompounds and constituting red to orange powders easily soluble in water with orange to red coloration, dissolving in sulphuric acid with blue to 8 violet red coloration and dyeing cotton of red orange to yellowish orange tints.

In witness whereof I have hereunto signed my name this 26th day of November,

ALFRED RHEINER. 

